During his 15-year reign, Domitian managed to incite most of Rome’s Germanic and Danubian neighbors to war without securing a significant victory. At the same time, his authoritarian manner alienated the Senate. In 96 AD he was assassinated in a palace conspiracy and the Senate proclaimed the 66-year-old Nerva as his successor. As the first of what posterity would call the “Five Good Emperors”, Nerva would usher in almost a century of Roman prosperity and stability under the Nerva–Antonine dynasty.
In January 89 AD Lucius Antonius Saturninus, governor of Germania Superior, led the Legio XIV Gemina and Legio XXI Rapax in revolt against Rome. Expecting his Chatti allies to cross the frozen Rhine to come to his support, Saturninus was thwarted when the river unexpectedly thawed, allowing Domitian’s general Lucius Appius Maximus Norbanus to swiftly suppress the revolt. Saturninus and many alleged co-conspirators were executed, and the Legio XXI was sent to Pannonia.in wikipedia
In 89 AD, for uncertain reasons, the Roman emperor Domitian ordered the invasion of the Iazyges, Quadi, and Marcomanni—all Roman client tribes up until this point. Few details of the war are known, except that the Romans were repelled.in wikipedia
In early 92 AD the Iazyges, Roxolani, Dacians, and Suebi crossed the Danube and invaded the Roman province of Pannonia. When the Quadi and Marcomanni refused Roman emperor Domitian’s call to supply troops, he declared war on them as well. In May the invaders destroyed the Roman Legio XXI Rapax in battle, but appear to have been defeated by January 93. After this the Danubian tribes probably resumed their positions as Roman clients, but remained restive until the beginning of Trajan’s reign (98).in wikipedia
On 18 September 96 AD the Roman emperor Domitian was assassinated in a palace coup involving members of the Praetorian Guard and several court officials, following which the 66-year-old former consul Nerva was declared emperor by the Senate. Nerva faced difficulties asserting his authority, with many in the army and Praetorian Guard remaining sympathetic to Domitian. In October 97 the Praetorian Guard revolted and forced him to adopt an heir. Nerva chose the general Trajan, who succeeded Nerva after he died of a stroke in January 98. By setting up a stable succession, Nerva started the century-long Nerva–Antonine dynasty and is considered one of the “Five Good Emperors”.in wikipedia